In a display skill field, a flat panel display possesses advantages of being ultra thin, power saved and radiation free. It has been widely utilized. A present flat panel display, such as a LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Display) has been gradually replacing the CRT displays and becomes a mainstream of the display devices.
The OLED possess many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, fast response, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED generally comprises a substrate, ITO transparent anode located on the substrate, a Hole Injection Layer (HIL) located on the ITO transparent anode, a Hole Transporting Layer (HTL) located on the Hole Injection Layer, an Emitting Material Layer (EML) located on the Hole Transporting Layer, an Electron Transport Layer (ETL) located on the Emitting Material layer, an Electron Injection Layer (EIL) located on the Electron Transport Layer and a Cathode located on the Electron Injection Layer.
The LCD in general includes a shell, a liquid crystal display panel in the shell and a backlight module located oppositely to the liquid crystal display panel and in the shell. The structure of the liquid crystal panel comprises a TFT substrate, a color filter substrate and a liquid crystal layer positioned between the two substrates. The working theory is to apply driving voltages to the two glass substrates to control the rotations of the liquid crystal molecules to refract out the light of the backlight module for generating images.
In the manufacture process of the OLED or the LCD, the glass substrate requires the processes of cleaning, film coating, photoresist coating, exposure, development, etching and etc to form a TFT substrate. The etching process can be a dry etching or a wet etching. The wet etching is to utilize the etching liquid, generally a strong acid or strong base liquid to remove the thin film without the cover of the photoresist by chemical etching and to form a desired circuit pattern on the substrate.
As shown in FIG. 1, which is a top view diagram of a present substrate delivery device utilized in a Low Temperature Poly-Silicon (LTPS) TFT substrate in a wet etching process according to prior art. The present substrate delivery device comprises a plurality of first delivery rollers 200 parallel to one another in an etching chamber 10 and a plurality of second delivery rollers 400 parallel to one another in a cleaning chamber 300. The first delivery rollers 200 and the second delivery rollers 400 directly load and deliver the glass substrate 500. The back side of the glass substrate 500 directly contacts the first delivery rollers 200 in the etching chamber 10 and the second delivery rollers 400 in a cleaning chamber 300. In the etching chamber 10, the hydrofluoric acid (HF) is employed for implementing etching to the glass substrate 500, the first delivery rollers 200 can easily contact the hydrofluoric acid and to be splashed with. Then, the first delivery rollers 200 can transfer the hydrofluoric acid on the back side of the glass substrate 500. When the concentration of the hydrofluoric acid reaches up over 3%. The corrosion to the glass substrate 500 will occur to cause the issue of uneven brightness of the back side of the substrate 500. The yield of the products is affected, which leads to the descending market competitiveness of the products.